The present invention relates, in general, to semiconductor processing, and more particularly, to a semiconductor structure processing method using a novel environmental gas mixture.
The semiconductor industry previously has utilized polycide in the formation of various low resistance semiconductor device structures including conductors and gate electrodes of field effect transistors. The polycide generally includes a polysilicon layer that is covered by a metal silicide. During the formation of semiconductor devices utilizing polycide, it is often necessary to expose the polycide to high temperatures, greater than approximately 900 degrees Celsius (900.degree. C.). Such exposure typically occurs during subsequent processing operations such as high temperature drive-in of ion implants. At the high temperatures, localized regions of the polycide often deform resulting in a concave or slumping shape in the localized region. It is difficult to maintain low resistance connections to such slumping structures. Often, the slumping is sufficiently severe to allow the metal silicide to contact underlying layers and structures thereby degrading the device's operating characteristics.
Accordingly, it is desirable to have a method of heating polycide that does not cause the polycide to deform, and that does not result in concave or slumping polycide structures.